RIYADH (Reuters) - Saudi Arabia is expected to announce a slight rise in its crude oil and gas reserves on Wednesday after being independently audited, according to a source familiar with the matter.

Saudi Arabia’s reserves of easily recoverable oil have long been the world’s largest.

For almost 30 years - despite rising production, large swings in oil prices and improved technology - Riyadh has annually reported the same number for reserves at around 261 billion barrels, according to a statistical review by BP.

An independent external audit of Saudi Aramco’s oil reserves - an essential part of the preparatory work for its planned initial public offering - found the state oil giant to have higher oil and gas reserves than it previously reported, sources familiar with the matter told Reuters in April.

Saudi Energy Minister Khalid al-Falih is due to hold a news conference in Riyadh on Wednesday to make the announcement at around 11.30 local time (0830 GMT).

He is also expected to provide further updates on the country’s energy strategy.